JP2013053744A - Torsional damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reduction of vibration proof performance by effectively suppressing the accumulation of heat to an elastic body by enhancing the circulation of air in a torsional damper.SOLUTION: The torsional damper has a hub 1, annular mass bodies 22, 32 coaxially arranged in the outer peripheral side of the supporting cylinder part 13 of the hub 1, and damper parts 2, 3 comprising elastic bodies 23, 33 for elastically coupling the hub 1 and the annular mass bodies 22, 32, air circulation cutouts 13a are opened and arranged in the supporting cylinder part 13, and fins 34 extending to the inner peripheral side of the supporting cylinder part 13 and in the rotational direction of the hub 1 are arranged in the air circulation cutouts 13a.

Description

  The present invention relates to a torsional damper that absorbs torsional vibration generated in a rotating shaft such as a crankshaft of an automobile engine.

  A so-called torsional damper that is attached to a crankshaft of an engine of an automobile or the like in order to prevent the occurrence of problems due to an increase in the amplitude of torsional vibration (vibration in the rotational direction) that accompanies rotation, so-called two sets of damper portions are provided. There is a double-mass type torsional damper.

  FIG. 16 shows an example of a conventional double-mass type torsional damper. A first hub 101 attached to the shaft end of the crankshaft at an inner peripheral boss 101a, and an outer peripheral side of the first hub 101 are shown. The annular mass body 102 arranged concentrically with the elastic body 103 via an elastic body 103 integrally vulcanized and molded with a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity) therebetween. The second hub 201 includes a first damper portion 100 having a coupled structure, and is coupled to one axial direction side of the first hub 101 by a plurality of screws 204 in the circumferential direction. A second damper part 200 having a structure in which an annular mass body 202 arranged concentrically on the outer peripheral side is elastically connected between both members via an elastic body 203 integrally molded with a rubber-like elastic material is provided. Preparation That. The first damper unit 100 and the second damper unit 200 have different torsional direction resonance frequencies (see, for example, Patent Document 1 below).

  In this type of torsional damper, the elastic bodies 103 and 203 absorb and attenuate torsional vibrations by converting kinetic energy into thermal energy. In other words, the elastic bodies 103 and 203 receive input of torsional vibrations. In response to repeated deformation, heat is generated by internal friction. In general, in the double-mass type torsional damper, since the air flow between the first damper part 100 and the second damper part 200 is poor, the elastic bodies 103 and 203 deteriorate due to heat accumulation, and the required performance is obtained. May not be obtained.

  Therefore, in the prior art shown in FIG. 16, a plurality of screws 204 that couple the first hub 101 and the second hub 201 to the outside (front side) of the second damper portion 200 are used. The blade member 300 is attached via the spacer 301, and the second damper portion 200 bypasses from the front side through the inner peripheral space of the tubular portion 300 a of the blade member 300 by the centrifugal pump action of the blade member 300 during rotation. A flow F of air passing through the front space to the outer diameter side is induced to promote heat dissipation (see Patent Document 1 below).

JP-A-8-326846

  However, according to the above prior art, since the air flow F passes through the front space of the second damper portion 200 to the outer diameter side, between the first damper portion 100 and the second damper portion 200. The air flow was still poor and the air cooling effect was not sufficient. In addition, since the blade member 300, which is a separate member from the torsional damper main body, and the plurality of spacers 301 for attaching the blade member 300 are used, there is a problem that the number of parts increases and the cost increases.

  Also, even a so-called single-mass type torsional damper that has only one set of damper parts has a poor air flow between the torsional damper and the engine on the back side, and heat dissipation from the elastic body is not sufficient. There was no case.

  The present invention has been made in view of the above points, and its technical problem is to effectively suppress the accumulation of heat in the elastic body by improving the air flow in the torsional damper. Therefore, it is to prevent the vibration-proof performance from being lowered.

  As a means for effectively solving the technical problem described above, a torsional damper according to the invention of claim 1 includes a hub, an annular mass disposed concentrically on the outer peripheral side of a support cylinder portion of the hub, A damper portion made of an elastic body that elastically connects the hub and the annular mass body, and a ventilation cutout is formed in the support cylinder portion of the hub, and the ventilation cutout includes an inner peripheral side of the support cylinder portion and the hub Fins extending in the rotational direction are arranged.

  A torsional damper according to a second aspect of the present invention is the torsional damper according to the first aspect, wherein a plurality of damper portions are arranged apart from each other in the axial direction, and a ventilation notch and fins are disposed between the plurality of damper portions. It is located in.

  According to a third aspect of the present invention, in the torsional damper according to the first or second aspect, the elastic body is concentrically arranged on the outer peripheral side of the sleeve fitted into the support cylinder portion of the hub. The annular mass is formed between the sleeves, and the fins are extended from the sleeve.

  According to a fourth aspect of the present invention, the torsional damper is characterized in that, in the configuration described in any one of the first to third aspects, the gradient of the fin with respect to the circumferential direction is large on the ventilation notch side and smaller on the tip side. It is.

  According to the torsional damper according to the present invention, during rotation, the air scooping action of the fins and the centrifugal force cause a significant airflow that flows from the inner peripheral space of the support cylindrical portion of the hub to the outer peripheral side through the ventilation notch. As a result, the heat generated by the elastic body in the damper portion is efficiently released, so that deterioration of the elastic body due to heat accumulation can be prevented and the initial vibration isolation performance can be maintained. In particular, in the case where a plurality of damper parts are arranged apart from each other in the axial direction, a significant air current flowing in the space between the damper parts to the outer peripheral side is generated, thereby being generated in the elastic body of each damper part. Heat can be released efficiently.

  Further, since the fins are formed to extend from the sleeve, the number of parts due to the attachment of the fins does not increase.

  Further, by making the fin shape have a larger gradient on the ventilation notch side and a smaller gradient on the tip side, the scooping action of air by rotation becomes more remarkable, so the heat dissipation effect can be improved.

1 is a perspective view showing a first embodiment of a torsional damper according to the present invention. 1 is a cross-sectional view showing a first embodiment of a torsional damper according to the present invention cut by a plane passing through an axis O. FIG. It is sectional drawing cut | disconnected and shown by the III-III line | wire of FIG. It is the fragmentary sectional view which expanded a part of FIG. It is a perspective view of a hub in a first embodiment of a torsional damper according to the present invention. It is a perspective view which shows the fitting state of the hub and 2nd damper part in 1st embodiment of the torsional damper which concerns on this invention. FIG. 4 is a half cross-sectional view showing a state before assembly in the first embodiment of the torsional damper according to the present invention, cut along a plane passing through the axis O; FIG. 6 is a half sectional view showing a torsional damper according to a second embodiment of the present invention by cutting along a plane passing through an axis O; It is sectional drawing cut | disconnected and shown by the IX line orthogonal to the axial center O in FIG. FIG. 6 is a half sectional view showing a third embodiment of the torsional damper according to the present invention by cutting along a plane passing through an axis O; It is sectional drawing cut | disconnected and shown by the XI line orthogonal to the axial center O in FIG. FIG. 10 is a half cross-sectional view showing a state before assembly in the third embodiment of the torsional damper according to the present invention by cutting along a plane passing through the axis O; FIG. 10 is a half sectional view showing a fourth embodiment of the torsional damper according to the present invention by cutting along a plane passing through the axis O; It is the figure seen from the back side of FIG. FIG. 10 is a half sectional view showing a fifth embodiment of the torsional damper according to the present invention cut along a plane passing through the axis O; FIG. 6 is a half sectional view showing an example of a conventional double-mass type torsional damper cut along a plane passing through an axis O;

  Hereinafter, preferred embodiments of a torsional damper according to the present invention will be described with reference to the drawings. In the following description, the “front side” means the left side in FIG. 2 and the front side of the vehicle, and the “back side” means the right side in FIG. 2 and there is an internal combustion engine (not shown). That is the side.

  First, as shown in FIGS. 1 and 2, the torsional damper according to the first embodiment includes a hub 1 and first damper portions 2 that are attached to the outer periphery of the hub 1 and are spaced apart from each other in the axial direction. And the 2nd damper part 3 is provided.

  The hub 1 is manufactured by casting a metal material or the like. As shown in FIGS. 5 and 7, the hub 1 is an inner cylinder portion 11 fixed to the crankshaft, and an intermediate portion 12 extending radially from the outer periphery thereof. And a support cylinder 13 extending in a cylindrical shape from the outer diameter end. Reference numeral 11 a is a keyway formed in the inner peripheral shaft hole of the inner cylinder portion 11.

  The first damper portion 2 is manufactured by casting a metal material 21 that is concentrically disposed on the outer peripheral side of the metal sleeve 21 that is fitted to the outer peripheral surface near the back surface of the support cylinder portion 13 of the hub 1. An annular mass body 22, and an annular elastic body 23 made of a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity) for elastically connecting the annular mass body 22 to the outer peripheral surface of the sleeve 21; Consists of. The elastic body 23 is integrally vulcanized and molded (vulcanized and bonded) with a rubber-like elastic material between the outer peripheral surface of the sleeve 21 and the inner peripheral surface of the annular mass body 22, that is, the first damper. The part 2 has a bush type structure. On the end surface of the annular mass body 22 on the second damper portion 3 side, as shown in FIGS. 3 and 4, a recess 22a (in other words, a rib 22b between the recesses 22a) opened to the outer diameter side is circumferential. Many are formed at equal intervals in the direction.

  The second damper portion 3 is concentrically arranged on the outer peripheral side of a metal sleeve 31 fitted to the outer peripheral surface near the front side of the support cylinder portion 13 of the hub 1 and is manufactured by casting a metal material or the like. An annular mass body 32, and an annular elastic body 33 made of a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity) that elastically connects the annular mass body 32 to the outer peripheral surface of the sleeve 31; Consists of. The elastic body 33 is integrally vulcanized (vulcanized and bonded) with a rubber-like elastic material between the outer peripheral surface of the sleeve 31 and the inner peripheral surface of the annular mass body 32. The damper part 3 also has a bush type structure.

  The first damper portion 2 and the second damper portion 3 have different resonances due to the difference in the circumferential inertia mass of the annular mass bodies 22 and 32 and the difference in the circumferential shear spring constant of the elastic bodies 23 and 33. The frequency is set.

  A plurality of openings 12 a are formed in the intermediate portion 12 of the hub 1 at equal intervals in the circumferential direction, and the support cylinder portion 13 is positioned between the first damper portion 2 and the second damper portion 3. A plurality of ventilation notches 13a are opened at equal intervals in the circumferential direction, and fins 34 are disposed in each ventilation notch 13a.

  The sleeve 31 of the second damper part 3 has an end part 31a facing the back side protruding from the inner periphery of the elastic body 33 to the back side, and the fins 34 arranged in the ventilation notches 13a in the hub 1 are It extends from the end 31a. In detail, the fin 34 passes from the rear end 31a of the sleeve 31 of the second damper portion 3 through the ventilation notch 13a to the inner peripheral side of the support cylinder portion 13 and the rotation direction of the hub 1 (FIGS. 3 and FIG. 4 is formed in a gentle S-shaped curved surface in which the gradient with respect to the circumferential direction is large on the ventilation notch 13a side and is small on the tip side.

  The torsional damper is assembled by fitting the sleeve 21 in the first damper part 2 and the sleeve 31 in the second damper part 3 on the outer peripheral surface of the support cylinder part 13 of the hub 1.

  Here, in the state before assembly shown in FIG. 7, an L-shaped notch formed of a portion extending in the axial direction and a portion extending in the circumferential direction is formed in the end portion 31 a on the back side of the sleeve 31 in the second damper portion 3. A tongue piece 34 a is formed by 31 b, and when the sleeve 31 is press-fitted to the outer peripheral surface of the support cylinder portion 13 of the hub 1, the tongue piece 34 a of the sleeve 31 is opened to the support cylinder portion 13. Positioning is performed in the circumferential direction so as to coincide with the notch 13a in phase. Since each tongue piece 34a is positioned in each ventilation notch 13a by press-fitting the sleeve 31 to the outer peripheral surface of the support cylinder portion 13 of the hub 1 to a predetermined axial position, Fins 34 as shown in FIG. 6 are formed by punching the pieces 34a toward the inner peripheral side and bending them.

  The torsional damper according to the first embodiment configured as described above is attached to the crankshaft of the internal combustion engine at the inner cylinder portion 11 of the hub 1, and rotates with the crankshaft via the hub 1. The first damper portion 2 or the second damper portion 3 resonates with a phase angle different from that of the input vibration in a frequency range where the amplitude of the torsional vibration of the crankshaft inputted in this way becomes maximum, and the torque due to the resonance motion is By causing the torque of the input vibration to cancel out, the peak of the torsional vibration of the crankshaft is effectively reduced. And since the different resonance frequency is set to the 1st damper part 2 or the 2nd damper part 3, the outstanding damping function can be show | played in a wide rotation speed range.

  Here, the torsional damper rotates in the clockwise direction in FIGS. 3 and 4, so that the fins 34 formed on the end 31 a on the back side of the sleeve 31 in the second damper portion 3 are connected to the hub 1. The pumping function of scooping up the air existing in the inner peripheral space of the support cylinder portion 13 toward the outer peripheral side is achieved. Moreover, since centrifugal force also acts on the air scooped up by the rotation of the fin 34, it is scooped up by the fin 34 from the front side of the torsional damper through the inner peripheral space of the support cylinder portion 13 of the hub 1 and passes through the ventilation notch 13a. Thus, the space between the first damper portion 2 and the second damper portion 3 is discharged to the outer peripheral side.

  In addition, since the fin 34 is formed in a gentle S-shaped curved surface in which the gradient with respect to the circumferential direction is large on the ventilation notch 13a side and becomes smaller on the tip side, the tip of the fin 34 is in the rotation direction. The air pump cuts air, scoops up along the curved surface of the middle part of the fin 34 where the gradient gradually increases, and exerts a remarkable pumping action that throws it out to the outer peripheral side.

  In addition, since a large number of recesses 22a and ribs 22b are alternately formed in the circumferential direction on the end surface of the annular mass body 22 of the first damper portion 2 on the second damper portion 3 side, this is a centrifugal type. It functions like an impeller and has a pumping action of releasing air existing in the space between the first damper portion 2 and the second damper portion 3 to the outer peripheral side by centrifugal force. For this reason, the remarkable airflow F as shown with a broken line in FIG.2 and FIG.4 is produced by cooperation with the pump action by the fin 34. FIG. A part of the air flow F in the inner peripheral space of the support cylinder portion 13 of the hub 1 also flows from the back side of the torsional damper through the opening portion 12a of the intermediate portion 12 of the hub 1.

  The elastic body 23 in the first damper portion 2 and the elastic body 33 in the second damper portion 3 absorb and attenuate torsional vibrations by converting kinetic energy into heat energy. Since the bodies 23 and 33 are repeatedly subjected to shear deformation in accordance with the torsional direction resonance operation of the first damper portion 2 and the second damper portion 3, they generate heat due to internal friction, but as described above, the first damper portion Since a significant air flow F is generated in the space between 2 and the second damper portion 3, the heat generated by the elastic bodies 23 and 33 is efficiently removed by this air flow F. Therefore, heat is not trapped between the first damper portion 2 and the second damper portion 3, and the elastic bodies 23 and 33 are deteriorated in material due to heat and change in characteristics due to this, or cracks occur. It is possible to effectively prevent the occurrence of noise and maintain the initial vibration isolation performance.

  Moreover, since the fins 34 extend from the sleeve 31 of the second damper portion 3, the number of parts does not increase.

  Note that the fins 34 may be formed on the sleeve 21 of the first damper portion 2.

  8 and 9 show a second embodiment of the torsional damper according to the present invention. That is, the second embodiment is different from the first embodiment described above in that the fins are formed on the support cylinder portion 13 of the hub 1 instead of the sleeve 31 or the sleeve 21.

  Specifically, the hub 1 is manufactured by press forming a metal plate or the like, and includes a support cylinder portion 13 and a disk portion 14 extending from an end portion on the back surface side to an inner diameter side. The shaft hole 14a is inserted through the crankshaft. Then, the fin 15 is circumferentially formed by a method in which an intermediate portion in the axial direction of the support cylinder portion 13 of the hub 1, that is, a portion between the first damper portion 2 and the second damper portion 3 is formed in a tongue shape toward the inner diameter side. A plurality of holes are formed at equal intervals in the direction, and a portion where the support cylinder portion 13 is opened by punching the fin 15 is a ventilation notch 13a.

  The fin 15 extends on the inner peripheral side of the support cylinder portion 13 (ventilation notch 13a) and in the rotation direction of the hub 1 (clockwise direction in FIG. 9), and the gradient with respect to the circumferential direction is large on the vent notch 13a side. It is formed in a gentle S-shaped curved surface that becomes smaller toward the tip side.

  The torsional damper according to the second embodiment configured as described above also has a structure in which the tip of the fin 15 tears the air in the direction of rotation with rotation and the middle part of the fin 15 where the gradient gradually increases. Scooping up along the curved surface and throwing out to the outer peripheral side, and a large number of recesses 22a and ribs 22b formed in the annular mass body 22 of the first damper portion 2 function like a centrifugal impeller Therefore, a significant air flow is generated by cooperation with the pump action by the fins 15, and the same heat dissipation effect as that of the first embodiment can be realized.

  In addition, since the fins 15 are formed in the supporting cylinder portion 13 of the hub 1 together with the ventilation notches 13a at a time, the structure can be further simplified.

  10 and 11 show a third embodiment of the torsional damper according to the present invention. In both the first and second embodiments described above, the elastic bodies 23 and 33 in the first and second damper portions 2 and 3 are fitted to the outer peripheral surface of the support cylinder portion 13 of the hub 1. It is a bush-type structure integrally vulcanized (vulcanized and bonded) with a rubber-like elastic material between the sleeves 21 and 31 made of an annular material and the annular mass bodies 22 and 32 arranged concentrically on the outer periphery thereof. On the other hand, the third embodiment shown in FIGS. 10 and 11 uses the first and second damper portions 2 and 3 as fitting types.

  Specifically, the elastic bodies 23 and 33 in the first and second damper portions 2 and 3 are press-fitted between the support cylinder portion 13 of the hub 1 and the annular mass bodies 22 and 32 arranged concentrically on the outer peripheral side thereof. Are combined. As in the second embodiment shown in FIGS. 8 and 9, the hub 1 is manufactured by press molding of a metal plate or the like, and extends from the support cylinder portion 13 and the back side end portion toward the inner diameter side. It consists of a disk part 14, and the inner diameter of the disk part 14 is a shaft hole 14a through which the crankshaft is inserted. Further, the inner peripheral surfaces of the support cylinder portion 13 and the annular mass bodies 22 and 32 of the hub 1 are formed in a undulating shape that undulates in the radial direction corresponding to each other. Similarly to this, 33 also meanders in the radial direction at the axially intermediate position, thereby stabilizing the fitted state.

  The fin 15 is an axially intermediate portion of the support cylinder portion 13 of the hub 1, that is, a portion between the first damper portion 2 and the second damper portion 3 (a portion between the fitting positions of the elastic bodies 23 and 33). Are formed at equal intervals in the circumferential direction by a method such as punching out into the inner diameter side, and a portion where the support cylinder portion 13 is opened by punching out the fins 15 is a ventilation notch 13a. And the fin 15 is extended in the rotation direction (clockwise direction in FIG. 11) of the hub 1 and the inner peripheral side of the support cylinder part 13 (ventilation notch 13a) similarly to 2nd embodiment, and the circumferential direction Is formed in a gentle S-shaped curved surface that has a large slope on the ventilation notch 13a side and a smaller slope on the tip side.

  Therefore, the torsional damper of the third embodiment also scoops up the air in the direction of rotation of the fin 15 as it rotates, and scoops up the curved surface of the fin 15 where the gradient gradually increases, While having a remarkable pumping action of throwing to the outer peripheral side in cooperation with the centrifugal force, a large number of recesses 22a and ribs 22b formed in the annular mass body 22 of the first damper portion 2 function like an impeller. A significant air flow is generated by cooperation with the pumping action of the fins 15, and the same heat dissipation effect as in the first embodiment can be realized.

  Further, as shown in FIG. 12, this torsional damper has annular mass bodies 22 and 32 disposed on the outer periphery of the support cylinder portion 13 of the hub 1 in which the ventilation notches 13a and the fins 15 are previously formed, and the shaft of the ventilation notches 13a. Concentrically arranged so as to be located on both sides in the direction, the elastic body 23 is press-fitted from the back side between the outer peripheral surface of the support cylinder 13 and the inner peripheral surface of the annular mass body 22, and the elastic body 33 is It is assembled by press-fitting from the front side between the outer peripheral surface of the support cylinder part 13 and the inner peripheral surface of the annular mass body 32.

  Next, FIGS. 13 and 14 show a fourth embodiment of the torsional damper according to the present invention. In each of the above-described embodiments, the present invention is applied to a double-mass type torsional damper, whereas the fourth embodiment shown in FIGS. 13 and 14 is a single-mass type. This applies to the torsional damper.

  That is, the single-mass type torsional damper includes a hub 1 and a single damper portion 4 attached to the outer periphery of the hub 1.

  Specifically, the hub 1 is manufactured by press molding of a metal plate, and includes a support cylinder portion 13, an outer diameter side disk portion 16 extending from the front end portion to the inner diameter side, and a conical shape on the inner diameter side. The inner diameter side disk portion 18 is formed to be unevenly distributed to the back side from the outer diameter side disk portion 16 via the cylinder portion 17, and the inner diameter of the inner diameter side disk portion 18 becomes a shaft hole 18 a through which the crankshaft is inserted. ing. A plurality of ventilation windows 16 a are formed in the outer diameter side disk portion 16 at predetermined intervals in the circumferential direction.

  The damper portion 4 includes a metal sleeve 41 fitted on the outer peripheral surface of the support cylinder portion 13 of the hub 1, an annular mass body 42 concentrically arranged on the outer peripheral side and manufactured by casting a metal material, and the like. An annular elastic body 43 made of a rubber-like elastic material that elastically connects the annular mass body 42 to the outer peripheral surface of the sleeve 41. The elastic body 43 is integrally vulcanized (vulcanized and bonded) with a rubber-like elastic material between the outer peripheral surface of the sleeve 21 and the inner peripheral surface of the annular mass body 22. Has a bush type structure.

  An end on the back side of the support cylinder portion 13 of the hub 1 protrudes from an end on the back side of the sleeve 41 in the damper portion 4, and a plurality of fins 15 are formed at equal intervals in the circumferential direction on the protrusion. ing. The fin 15 is formed by a method in which the end portion on the back side of the support cylinder portion 13 is ejected in a tongue shape toward the inner diameter side, and the portion where the support cylinder portion 13 is cut by striking the fin 15 is vented. It becomes the notch 13a. And this fin 15 is extended in the rotation direction (counterclockwise direction in FIG. 14) of the inner periphery side of the support cylinder part 13 (ventilation notch 13a) and the hub 1 like 2nd and 3rd embodiment. In addition, it is formed in a gentle S-shaped curved surface in which the gradient with respect to the circumferential direction is large on the ventilation notch 13a side and becomes smaller on the tip side.

  According to the torsional damper of the fourth embodiment configured as described above, the tip of the fin 15 tears the air in the rotation direction with rotation, and the inside of the fin 15 where the gradient gradually increases. It scoops up along the curved surface of the abdomen and produces a remarkable pumping action that throws it out to the outer periphery by centrifugal force. Accordingly, air on the front side of the torsional damper flows into the inner peripheral space of the support cylinder part 13 through the ventilation window 16a opened in the outer diameter side disk part 16 of the hub 1, so that a broken line arrow in FIG. As shown in FIG. 3, a remarkable air flow that passes from the front side of the torsional damper to the outer diameter side between the back surface of the damper portion 4 and the engine through the ventilation window 16a, the inner peripheral space of the support cylinder portion 13, and the ventilation notch 13a. F is produced.

  For this reason, high-temperature air does not stay between the torsional damper and the engine (not shown) on the back side, and heat dissipation from the elastic body 43 can be performed efficiently.

  FIG. 15 shows a fifth embodiment of the torsional damper according to the present invention. This torsional damper is also a single mass type, and basically has the same configuration as that of the above-described fourth embodiment except that the damper portion 4 is a fitting type.

  Therefore, also in this embodiment, high-temperature air does not stay between the torsional damper and the engine (not shown) on the back side thereof, and heat dissipation from the elastic body 43 can be performed efficiently.

DESCRIPTION OF SYMBOLS 1 Hub 12a Opening part 13 Supporting cylinder part 13a Ventilation notch 15, 34 Fin 16a Ventilation window 2 First damper part 21, 31, 41 Sleeve 22, 32, 42 Annular mass body 22a Recessed part 22b Ribs 23, 33, 43 Elastic body 3 Second damper part 4 Damper part

Claims (4)

  A hub, an annular mass disposed concentrically on the outer peripheral side of the support cylinder portion of the hub, and a damper portion made of an elastic body that elastically connects the hub and the annular mass body; A torsional damper, wherein a ventilation notch is formed, and a fin extending in an inner peripheral side of the support cylinder portion and in a rotation direction of the hub is disposed in the ventilation notch.   2. The torsional damper according to claim 1, wherein a plurality of damper portions are arranged apart from each other in the axial direction, and the ventilation notch and the fin are located between the plurality of damper portions.   The elastic body is formed between a sleeve fitted to the supporting cylinder portion of the hub and an annular mass disposed concentrically on the outer peripheral side thereof, and the fin extends from the sleeve. The torsional damper according to claim 1 or 2.   The torsional damper according to any one of claims 1 to 3, wherein the gradient of the fin with respect to the circumferential direction is larger on the ventilation notch side and is smaller on the tip side.

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